CN101282715B

CN101282715B - Method of storing nanoparticle formulations

Info

Publication number: CN101282715B
Application number: CN2006800312295A
Authority: CN
Inventors: W·于; J·蒙
Original assignee: Celsion Corp
Current assignee: Imunon Inc
Priority date: 2005-08-23
Filing date: 2006-08-23
Publication date: 2013-03-27
Anticipated expiration: 2026-08-23
Also published as: TW200803918A; HK1120731A1; WO2007024826A3; ES2587583T3; CA2620829A1; WO2007024826A2; AU2006283465B2; TWI388344B; KR20120104438A; JP5227173B2; KR20080046672A; AU2006283465A1; EP1937214B1; CA2620829C; KR101209496B1; CN101282715A; JP2009506038A; EP1937214A2

Abstract

The present invention is a method of storing liposomal or nanoparticle formulations formed by combining at least one phospholipid, at least one surfactant and at least one hydrophilic polymer . The method includes freezing the formulation and storing it for a period of at least three days.

Description

The method of storing nanoparticle formulations

Background of invention

Background information

Several standard techniques have been used for the storage of liposome and nano-particle, such as cold preservation, freezing/dry (or lyophilizing), and dehydration.In freeze drying process, can use preservation filler (antifreezing agent) to strengthen storage such as sugar and sugar derivatives.These preserve that fillers help but the stability or the damage problem that always do not overcome fully liposome in freezing and the defreezing method.Aspect the economy of present method and the industrial efficiency limitation being arranged also, can cause shelf life limited under cold preservation or freezing conditions because mix this preservation filler.And, relevant with lyophilizing freezing, thaw and/or drying means or dewatering in, the harmful change to biology, chemistry and/or the physical property of the active agent of sealing can appear.Present freeze drying process (freezing and dry cycle) also may be very slow and consuming time.An important concern is that if lyophilizing is carried out too soon or carried out under unsteered temperature, then it may cause the change of biology, chemistry and/or the physical property of liposome membrane, thereby causes storing unstability.Finally, this also may detrimentally affect the character of the active agent of sealing.

Use separately or with conventional freezing method that other method is combined with in, for example since be exposed to the film formed high pressure of liposome vesicle that ice crystal forms mechanical stress or freezing, thaw and/or dehydration in expansion and the contraction of solute in the liposome, may cause damage.The expansion of liposome membrane can cause weakness in the liposome membrane and the formation of fistula and crackle in the freeze cycle process, and the loss that this causes again integrity and stability causes leakage problem.In addition, single liposome is mutual bunchy closely usually, so that in the refrigerating process of routine, the expansion of a liposome may cause pressure, causes the negative consequence to the adjacent liposomes integrity.

Usually, prior art has its limitation in the following areas: the shelf life of liposome, and storage, processing and embedding character, and keep (i) liposome or Nanoparticulate compositions; (ii) ability of the integrity of active agent.In addition, many technology are owing to the size of the length of finishing the required time of technique and the processing batch of material that causes thus has extra limitation, and this has increased resulting cost.

Invention field

The method of relate generally to storing nanoparticle of the present invention.More specifically, the present invention relates to store the method for the liposome of stability with raising and storage characteristics.

Summary of the invention

The present invention is a kind of method that stores liposome or nanoparticle formulations, and this liposome or nanoparticle formulations form by making up at least a phospholipid, at least a surfactant and at least a hydrophilic polymer.The method comprises freezing this preparation and it is stored at least three days time.

Invention is described

Embodiment of the present invention are discussed below.In describing embodiment, in order to know purpose, use concrete term.But, the invention is not restricted to the concrete term of so selecting.Although concrete exemplary embodiment has been discussed, should be understood that, doing so only is for illustrative purposes.Those skilled in the relevant art will appreciate that, can use other component and structure, and without departing from the spirit and scope of the present invention.The list of references of all references is incorporated herein by reference each piece quilt is introduced separately as it.

As used herein, nano-particle can be defined as general spherical vesicles, and it has by amphiphile and namely has skin or the film that the component of hydrophilic segment and hydrophobic part forms, and this skin or film are around kernel.Usually, the size of nano-particle is less than about 1000nm.What the present invention was concerned about especially is the nano-particle that can be used for or be used as drug delivery system.For example, be used for nano-particle of the present invention and can be used for sealing the chemical compound that is delivered to biosystem, this chemical compound includes but not limited to: (i) bioactive compound such as medicine; Or (ii) abiotic reactive compound such as photographic developer.Liposome be exemplary types can be used for nano-particle of the present invention.Liposome is vesicle, and it comprises the double-layer of lipoid around moisture nuclear, and it also can seal biological activity and abiotic reactive compound.The present invention strengthens and protection nano-particle or liposome membrane integrity, make its avoid various stress such as freezing, thaw and stir the damage that causes.Therefore, the present invention has improved stability, storage and/or the shelf life characteristics of nano-particle such as liposome.As used herein, freezing can being under any temperature is generally less than 0 ℃, and it provides solid-state, for example approximately-20 ℃ or following, approximately-78 ℃ or following (being dry-ice temperature), or approximately-196 ℃ or following (being liquid nitrogen temperature).Although usually described the present invention having liposome aspect the embodiment of representative nano-particle, this is not restrictive, and the present invention also is applicable to other nano-particle.

The compositions of various liposomees and other nanoparticle formulations is well-known in the art, opens industrial for medical science, cosmetics and other purpose.Liposomal formulation is the various lipids of different mol ratio and the combination that other composition includes but not limited to target part and bioactive substance.Method for preparing lipidosome generally is known.Liposome can be prepared into various sizes, and for example diameter greater than 500nm, and can be the single or multiple lift vesicle less than 20nm-.They can be used for sealing various materials for medical science and non medical goal.Liposome can be used for embedding active agent such as pharmacological activity reagent, flavouring agent, diagnostic reagent, nutrient, gene prod, abiology biologically active prod such as photographic developer, and composition thereof, and these reagent are transported to concrete position.But a subject matter of Liposomal formulation is it store to be used for research or commercial object and the ability (being shelf life) that do not have degradation of lipid and/or active agent to discharge.Therefore, pass in time that liposome leaks and degraded aspect Vesicle stability be subject matter.

Embodiment of the present invention relate to storing nanoparticle formulations such as Liposomal formulation, but go for the nano-particle that is made of amphiphile such as lipid of other type.Be applicable to preparation of the present invention and comprise the nano-particle with membrane component, it comprises at least a amphiphile, at least a surfactant and at least a hydrophilic polymer.Hydrophilic polymer can be unmodified; Be combined modification by addition functional group with nano-particular film; Perhaps chemical bonding is to other component of amphiphile, surfactant or nano-particular film.Modification is so that the membrane-bound example of hydrophilic polymer and nano-particle can comprise that the functional group of addition polarity or formation electric charge is with the stronger association of polar group of amphiphile or the surfactant of generation and film forming.Alternatively; hydrophilic polymer can covalent bonding to amphiphile or the surfactant of film forming; thereby it is present in the surface of nano-particle or liposome, and to protect and to keep its integrity, perhaps it can mix the inner lipid layer of liposome or nanoparticle formulations.Hydrophilic polymer can be bonded to amphiphile or surfactant by biodegradable or hydrolyzable key such as amide or ester bond or by more stable key such as amine or ehter bond.

Bound by theory does not believe that hydrophilic polymer provides protection to liposome or nano-particle membrane integrity in freezing, cold preservation, lyophilizing, dehydration and/or rehydration method.Protection nano-particle and liposome membrane integrity have been preserved physics, chemistry and the biological property of nano-particle and Liposomal formulation, have also kept embedding in nano-particle or the liposome or the character of any chemical compound of sealing.Therefore, liposome or nanoparticle formulations preserved embedding be used for medical science, veterinary and non-medical use as but be not limited to biotechnology, electronics, defence and agrotechnical encapsulation object, and allow Liposomal formulation to store and transportation with freezing state.

The ratio of amphiphile and surfactant is variable, and it can be the ratio of any suitable nano-particle or liposome desired use.Recognize, amphiphile and surfactant all can have two affine surface-active properties; Yet when two kinds of components had similarity, for this description, amphiphile can be considered to main membrane component, and surfactant is accessory constituent.Therefore, the ratio of amphiphile and surfactant is at least about 51: 49, can be greatly to 99: 1.In exemplary, the ratio of amphiphile and surfactant is at least about 70: 30, can be approximately 80: 20 or 90: 10.As known in the art, add the variation that surfactant can cause nano-particle or liposome physics or chemical property, with the character that realizes some expectation such as the reduction of phase transition temperature or membrane permeability.This variation of Nanoparticulate compositions within the scope of the present invention.

Hydrophilic polymer can be present in the film of nano-particle or liposome with various amounts, and this amount is about about 25 mole percents of 0.1-based on the total amount meter of amphiphile and surfactant.Be bonded in the embodiment of the phospholipid that forms liposome at hydrophilic polymer, contain the hydrophilic polymer of the 75-90 % by weight of having an appointment and the lipid of 25-10 % by weight, this is corresponding to the about phospholipid of the hydrophilic polymer modification of 33 mole percents of about 0.11-.As skilled in the art to understand, the amphiphile that the hydrophilic polymer of mole percent is changed into the modification of mole percent will depend on the molecular weight of unmodified amphiphile and the molecular weight of hydrophilic polymer.The calculating of ratio is that those skilled in the art are well-known.Embodiment of the present invention can comprise the hydrophilic polymer (for example approximately 3-approximately the modified amphiphile of 13 mole percents) of the about hydrophilic polymer of 3-20 mole percent (for example approximately 3-approximately the modified amphiphile of 27 mole percents) or 3-10 mole percent.Certain embodiments of the present invention are by the approximately modified amphiphile preparation of 5 mole percents of about 4-, thereby the approximately hydrophilic polymer of 4.5 mole percents of 2.5-is provided approximately.The optimised quantity of hydrophilic polymer can easily be determined by routine experiment by those skilled in the art.

The compositions and methods of the invention are effectively for nano-particle and the liposome by the preparation of various compositionss, and described compositions includes but not limited to the combination of phospholipid, Semen sojae atricolor lipid, phosphoethanolamine, cholesterol, fat melting rhzomorph (lysolipids), surfactant and composition thereof and at least a hydrophilic polymer such as Polyethylene Glycol, polyaeryloyl morpholine, poly--the 2-ethyl-2-oxazoline, polyvinylpyrrolidone, methoxy poly (ethylene glycol) (mPEG) and derivant and mixture.The example of phospholipid of the present invention includes but not limited to phosphatidylcholine, phosphatidyl glycerol, phosphatidylinositols, PHOSPHATIDYL ETHANOLAMINE and sphingomyelin.Be used for LYSO-PHOSPHATIDYLCHOLINE LYSOPC that representative surfactants of the present invention can include but not limited to that double-stranded phospholipid, fat melting rhzomorph, bile acid, myristoyl surfactant, palmityl surfactant, stearoyl surfactant, glycerin mono-fatty acid ester, ceramide, PEG-ceramide, C18-ether connects, polyethylene glycol-ethylene copolymer, block copolymer, fatty acid and composition thereof.The example that is used for fat melting rhzomorph of the present invention includes but not limited to MPPC (MPPC), single lauroyl phosphatidylcholine (MLPC), single myristoyl phosphatidylcholine (MMPC), MSPC (MSPC) and composition thereof.Be used for representative hydrophilic polymers of the present invention and include but not limited to Polyethylene Glycol, polyaeryloyl morpholine, poly--the 2-ethyl-2-oxazoline, polyvinylpyrrolidone, methoxy poly (ethylene glycol) (mPEG) and composition thereof.The example that is used for active agent of the present invention includes but not limited to pharmacological activity reagent, flavouring agent, diagnostic reagent, nutrient, gene prod, abiology biologically active prod such as photographic developer, and composition thereof.The active agent of exemplary types comprises for example anesthetics, antihistaminic, antineoplastic agent, antiulcerative, anti-outbreak medicine, muscle relaxant, immunosuppressant, anti-infective, NSAID (non-steroidal anti-inflammatory drug), photographic developer, nutrient and composition thereof.Exemplary antineoplastic agent includes but not limited to anthracycline drug such as amycin (doxorubicin) and Epirubicin (epirubicin); Taxanes is such as paclitaxel and taxotere; With platinum class medicine (platins) such as cisplatin, carboplatin and oxaliplatin.

One embodiment of the invention are used and are comprised phospholipid DPPC, fat melting rhzomorph MSPC and functionalised to comprise that the phospholipid of hydrophilic polymer such as DSPE-mPEG-2000 and/or DSPE-mPEG-5000 is such as 1; the Liposomal formulation of 2-distearyl acyl group-sn-glycerol-3-phosphate ethanolamine (DSPE), wherein hydrophilic polymer is connected to lipid by amido link.Comprise the phospholipid that mol ratio is low to moderate 90: 10: 1: the fat melting rhzomorph: the liposome composition of the phospholipid of hydrophilic polymer functionalized is proved to be effective in freezing and storage method.Therefore, the present invention has broad-based application, and it can be used to industrial liposome product to increase efficient and reduce production costs.The present invention can be used for any nano-particle or Liposomal formulation with the integrity of protection liposome at freezing, cold preservation, dehydration and freeze-drying process.

In one embodiment, the present invention relates to a kind of storage and have augmented performance such as the method for nanoparticle formulations such as the Liposomal formulation of stability, storage, embedding or release characteristics.Find, hydrophilic polymer is mixed the film of nano-particle such as liposome, strengthened stability, storage, embedding and the release characteristics of this vesicle.Comprise in nano-particle and Liposomal formulation that hydrophilic polymer has limited freezing, cold preservation, thaws, lyophilizing, dehydration or other are used for that auxiliary described preparation stores, harmful change of biology, chemistry and the physical property of stability and the caused nano-particle of method of processing or liposome membrane.Original membrane integrity is protected, keeps and/or has been strengthened in the existence of the hydrophilic polymer of therefore, being combined with nano-particle or Liposomal formulation.

In the past, can not effectively use separately in order to store liposome freezing.Most of liposome products have alarm tag, write: " please don't be freezing ".Such example is found on the label of commercially available product such as Doxil, AmBisome, DepoCyt and several lipid of cosmetics.Being used for preparation of the present invention can provide a kind of compositions, and wherein liposome and nano-particle can be frozen, and the content that does not damage film integrality or seal.Therefore, use preparation of the present invention will allow single bottle and many bottles of combination products to be frozen and to store to be used for distributing purpose.That is, special benefits of the present invention is, Liposomal formulation can be frozen and transport with single container, and it can be unit dosage form, rather than betransported with the container that separates, like that need to again preparation before at once using.

The present invention also comprises the method for preparation and storing nanoparticle or Liposomal formulation, and the method comprises that amphiphile or the lipid that will be fit to formation nano-particle or liposome composition mix with hydrophilic polymer, freezing and storage.This nano-particle and liposome can use the common known method in this area to form, for example by the amphiphilic component is mixed under suitable condition with aqueous solution.Suitable method is well-known to those skilled in the art.See for example U.S. Patent No. 6,200,598 and 6,726,925 of Needham; The U.S. Patent No. 5,094,854 of Ogawa, they are incorporated herein by reference.Nano-particle and liposome composition can store the short time in full minute or a few hours and longer time such as a couple of days, several weeks, several months or several years.

And described method allows nano-particle and Liposomal formulation to be distributed into unit dose with a plurality of or single bottle before or after freezing and storage.Nano-particle of the present invention and Liposomal formulation can be sealed at least a in the following material: cell toxicant and non-cytotoxicity medicine, gene prod or biological reagent, and abiology reagent such as photographic developer, it can use immediately or frozen-pack becomes test kit.

Another care in people and/or animal in the process of use nano-particle and liposome composition is, said composition can be identified and remove such as reticuloendothelial system (RES) by the defence of the health of nature, has limited their effective cycle time and therapeutic use.Check several method, prepared " stealthy (stealth) " compositions such as the size of optimization nano-particle and liposome composition or by in composition film, adding some composition removal biology process that they avoid nature with protection or " hiding ".In storage process, nano-particle and liposome tend to size to be increased, and causes the loss of film integrality and stability.As the replacement scheme of the independent composition of special adding this to produce " stealthy " characteristic, develop a kind of nano-particle and liposome size and inhomogeneity method of expecting of keeping, can help to increase and be kept among the experimenter effectively circulation time.Reason thus, the size of protection nano-particle or liposome in freezing, cold preservation, dehydration or freeze-drying process can be very important to their integrity and performance.Therefore, the preparation that improves nano-particle or liposome stability can keep particle size constant in storage process, has kept its treatment effectiveness.

In an exemplary, use known method, with the hydrophilic polymer of amphiphile, surfactant and the effective dose amphiphile of hydrophilic polymer (or be modified to comprise) combination, form nano-particle.For example, can be with amphiphile, surfactant and the hydrophilic polymer amphiphile of hydrophilic polymer (or be modified to comprise) combination in organic solvent, then desolventizing adds aqueous solution.Then active agent can be used known technology for example to utilize the pH gradient to be loaded into the inner space of nano-particle.Can use known technology for example to extrude the screening nano-particle by suitable polycarbonate filter.Screening can be carried out before or after loading nano-particle with active agent.Final nanoparticle size can or be the about about 500nm of 10-less than about 1000nm, the about about 500nm of 25-, approximately approximately 200nm or the about about 125nm of 80-of 50-.The effective dose of hydrophilic polymer can be determined by the following method: the preparation nano-particle, and freezing under the temperature of expectation, store the suitably long time, thaw said preparation and meter are shown the characteristic of the nano-particle of stability.The characteristic of measuring can be for example leakage of granular size or active agent.Then, the amount of hydrophilic polymer can change to realize the stability of expected degree in the initial preparation.

Behind the preparation nano-particle, preparation can be with solid-state for example approximately-20 ℃ or following, approximately-78 ℃ or following or freezing and store approximately-196 ℃ or under the following temperature.In exemplary embodiment, nano-particle can store approximately three days or more days with freezing state, and does not have significant physical property to change when thawing.In other embodiments, nanoparticle formulations can store approximately seven days or more days, and approximately one month or longer, approximately three months or longer, or approximately 24 months, or even the longer time.Said preparation can save as tank solution, perhaps before freezing, can be divided into unit dose to be used for distribution.Except storing, freezing nanoparticle formulations can be transported to it with the site that is used.For example, preparation can prepare in production equipment, is divided into unit dose, and is freezing and be transported to it with the position that is used.This provides the advantage that is better than existing preparation and distribution method.Use traditional method, nanoparticle formulations often is divided into the component part in order to transport, in order to prevent stability lost.For example, often with a plurality of bottle transportations, wherein liposome is in a container for Liposomal formulation, and the solution of active agent is in another container.Before use, two independent containers must be with the mode combination of guaranteeing that active agent loads before administration.The mistake for preparing in this final solution may cause lacking effectiveness.Utilize the present invention, removed this integrating step from.Therefore, using the site, preparation thaws, and can directly use or administration.This helps the use of compositions, and guarantees compositions correct preparation for effective administration.

Therefore, the invention provides the method for storage, transportation and administration nano-particle or Liposomal formulation.The preparation that stores and/or transport according to the present invention can be with any mode administration for this special preparation.That medication comprises is oral, rectum, peritoneum, vein and cheek administration, but can use the route of administration of any expectation according to active agent and avtive spot thereof.Said preparation can be individually dosed; Namely as prepared, perhaps be combined with other treatment reagent or excipient before use.Excipient can comprise other solid or liquid excipient such as aqueous solution, suspension, emulsion, solid excipient, dispersant etc.If nanoparticle formulations directly uses afterwards in preparation, namely before storing and transporting, use, then finally use consistent with the purposes of nanoparticle formulations.

Will be further understood that these and other feature and advantage of the present invention by following exemplary embodiment, described exemplary embodiment is not intended to limit the scope of the invention.

Exemplary embodiment 1

With dipalmitoyl phosphatidyl choline (DPPC), MSPC (MSPC) and N-(carbonyl-methoxy poly (ethylene glycol)-2000)-1,2-distearyl acyl group-sn-glycerol-3-phosphate ethanolamine (DSPE-mPEG-2000) is dissolved in dichloromethane with mol ratio at 90: 10: 4.Then remove organic solvent by rotary evaporation.Then mixture is used the hydration under pH4 of 300mM citrate buffer solution, obtain the approximately final lipid concentration of 100mg/ml.Then the suspension that forms extrudes (Hope by two polycarbonate membrane filters, M.J. etc., Production oflarge unilamellar vesicles by a rapid extrusion procedure, characterization of size, trapped volume and ability to maintaina membrane potential. Biochim. Biophys. Acta.812:55-65,1985).The initial particle mean size of the final Liposomal formulation among this embodiment is 98-122nm.(usually, the granularity of liposome of the present invention will be 50-500nm according to extrusion method.) by with liposome and sodium carbonate liquor and medicament mixed and the medicine amycin is loaded in the liposome.In brief, the 0.5mM sodium carbonate of the amycin solution (5.8mg/ml) of 1.6ml and 1.2ml is added in the liposome mixture of 1.9ml, in 35 ℃ of balances 60 minutes.Then with the liposome of drug loading and empty liposome in-20 ℃ of storages.The variation of monitoring granularity.The liposome composition that does not add mPEG by identical method preparation.Table 1 explanation, along with the adding of mPEG, liposome particle size freezing and thaw after keep identical, and recorded by liposome and the stability test of standard, liposome is stablized and is reached 24 months most.By contrast, the liposome that lacks hydrophilic polymer mPEG freezing and thaw after unstable.This instable evidence is that granularity is in freezing rear increase.Fig. 1 has shown the Liposomal formulation after the freeze/thaw.Before and after freeze/thaw, visual appearance and granularity do not have significant difference.

Table 1 freezing and thaw after liposome particle size change

Exemplary embodiment 2

As described in exemplary embodiment 1, the another kind of Liposomal formulation that contains amycin of preparation.

With sample freezing 1 weeks, 1 month and 3 months under-20 ℃.At each time point, measure that % under amycin content, the 1.2 μ m reclaims, % seals, liposome concentration, pH and vesicle size.At initial time point (t=0), be with or without three samples of freezing lower test, to determine freezing impact on Liposomal formulation.In addition, a sample is exposed to three freeze-thaw circulations, whether can be harmful to determine repeatedly the freeze-thaw circulation.

Can be found out by following table, when t=0, Liposomal formulation has similar characteristic under environment or freezing conditions.Even three freeze-thaw circulations do not affect film integrality yet.Preparation is still stable-20 ℃ of storage lifves through 3 months.In this time range, do not observe vesicle size, amycin content, seal or the significant change of lipid content.Although the outside pH of the sample that records has slight change at different time points, observe the pH measured value of the liposome that in carbonate buffer solution, prepares along with CO ₂Gas is run out of from bottle and is changed in time.But as shown in table 2, the variation of pH does not affect membrane stability, because 3 months pH data and the data class in when week are seemingly.

Table 2 is at repeat freezing with the liposome stability after thawing

The embodiment that exemplifies in this description and discuss only is intended to instruct the known preparation of those skilled in the art inventor and uses best mode of the present invention.All should not think Anywhere in this description limits the scope of the invention.All embodiment that provide all are representational and indefinitenesses.As skilled in the art to understand, in view of above-mentioned instruction, without departing from the invention, the above-mentioned embodiment of the present invention can modify or change.Therefore, should be understood that the present invention can implement in the mode outside the specifically described mode in the scope of claims and their equivalent.

The accompanying drawing summary

Fig. 1 show freezing according to the present invention and thaw after Liposomal formulation.

Claims

1. A method of storing a nanoparticle formulation, wherein the nanoparticle has (a) a film comprising at least one amphiphile, at least one surfactant, and at least one hydrophilic polymer, and (b) an embedded active agent selected from pharmacologically active agents; the method comprising freezing the nanoparticle formulation to form a frozen nanoparticle formulation and storing the frozen nanoparticle formulation for a period of at least one month, wherein said formulation is stable for said time.

2. The method of claim 1, further comprising transporting the frozen nanoparticle formulation and thawing the formulation at another location.

3. The method of claim 1, wherein the nanoparticles are liposomes.

4. The method of claim 3, wherein the amphiphile comprises at least one phospholipid.

5. The method of claim 4, wherein:

a. said at least one phospholipid is selected from the group consisting of phosphatidylcholine, phosphatidylglycerol, phosphatidylinositol, phosphatidylethanolamine, sphingomyelin and mixtures thereof;

b. The at least one surfactant is selected from the group consisting of double-chain phospholipids, lipolysin, bile acids, myristoyl surfactants, palmitoyl surfactants, stearyl surfactants, glycerol monooleate, Ceramides, PEG-ceramides, C18-ether-linked lysophosphatidylcholines, polyethylene glycol-polyethylene copolymers, block copolymers, fatty acids, and mixtures thereof; and

c. The at least one hydrophilic polymer is selected from polyethylene glycol, polyacrylmorpholine, poly-2-ethyl-2-oxazoline, polyvinylpyrrolidone, methoxypolyethylene glycol ( mPEG) and mixtures thereof.

6. The method of claim 5, wherein the hydrophilic polymer is bound to the phospholipid via a hydrolyzable bond.

7. A method of storing a liposome formulation, wherein said liposome has (a) a bilayer comprising at least one phospholipid, at least one surfactant, and at least one hydrophilic polymer, wherein said The phospholipid is at least one phosphatidylcholine; the surfactant is at least one lipolysin; and the hydrophilic polymer is selected from DSPE-mPEG-2000, DSPE-mPEG-5000 and mixtures thereof; and (b) an entrapped active agent selected from pharmacologically active agents; the method comprising freezing said liposome formulation to form a frozen liposome formulation and storing said frozen liposome Dosage for at least one month, wherein the formulation is stable during said time.

8. The method of claim 7, further comprising transporting said frozen liposomal formulation and thawing said formulation at another location.

9. The method of claim 7, wherein said phospholipid is at least one phosphatidylcholine; said surfactant is at least one selected from monopalmitoylphosphatidylcholine (MPPC), monolauroylphosphatidylcholine base (MLPC), monomyristoylphosphatidylcholine (MMPC), monostearylphosphatidylcholine (MSPC) and mixtures thereof; and said hydrophilic polymer is selected from DSPE-mPEG- 2000, DSPE-mPEG-5000 and mixtures thereof.

10. The method of claim 9, wherein said phospholipid is dipalmitoylphosphatidylcholine (DPPC); said surfactant is monopalmitoylphosphatidylcholine (MPPC); and said hydrophilic polymer selected from DSPE-mPEG-2000, DSPE-mPEG-5000 and mixtures thereof.

11. The method of claim 9, wherein said phospholipid is dipalmitoylphosphatidylcholine (DPPC); said surfactant is monostearylphosphatidylcholine (MSPC); and said hydrophilic polymeric The material is selected from DSPE-mPEG-2000, DSPE-mPEG-5000 and mixtures thereof.

12. The method of claim 10, wherein the molar ratio of DPPC:MPPC:DSPE-mPEG is about 90:10:4.

13. The method of claim 11, wherein the molar ratio of DPPC:MSPC:DSPE-mPEG is about 90:10:4.

14. The method of claim 1, wherein the active agent is selected from the group consisting of anesthetics, antihistamines, antineoplastics, antiulcers, antiseizures, muscle relaxants, immunosuppressants, anti-infectives, non-steroidal Body anti-inflammatory drugs, imaging agents, nutritional agents and mixtures thereof.

15. The method of claim 14, wherein the active agent is at least one antineoplastic drug.

16. The method of claim 15, wherein the active agent is doxorubicin.

17. The method of claim 3, wherein the active agent is selected from the group consisting of anesthetics, antihistamines, antineoplastics, antiulcers, antiseizures, muscle relaxants, immunosuppressants, antiinfectives, nonsteroidal Body anti-inflammatory drugs, imaging agents, nutritional agents and mixtures thereof.

18. The method of claim 17, wherein the active agent is at least one antineoplastic drug.

19. The method of claim 18, wherein the active agent is doxorubicin.

20. The method of claim 4, wherein the active agent is selected from the group consisting of anesthetics, antihistamines, antineoplastics, antiulcers, antiseizures, muscle relaxants, immunosuppressants, antiinfectives, nonsteroidal Body anti-inflammatory drugs, imaging agents, nutritional agents and mixtures thereof.

21. The method of claim 20, wherein said active agent is at least one antineoplastic drug.

22. The method of claim 21, wherein the active agent is doxorubicin.

23. The method of claim 5, wherein the active agent is selected from the group consisting of anesthetics, antihistamines, antineoplastics, antiulcers, antiseizures, muscle relaxants, immunosuppressants, anti-infectives, non-steroidal Body anti-inflammatory drugs, imaging agents, nutritional agents and mixtures thereof.

24. The method of claim 23, wherein said active agent is at least one antineoplastic drug.

25. The method of claim 24, wherein the active agent is doxorubicin.

26. The method of claim 6, wherein the active agent is selected from the group consisting of anesthetics, antihistamines, antineoplastics, antiulcers, antiseizures, muscle relaxants, immunosuppressants, anti-infectives, non-steroidal Body anti-inflammatory drugs, imaging agents, nutritional agents and mixtures thereof.

27. The method of claim 26, wherein said active agent is at least one antineoplastic drug.

28. The method of claim 27, wherein the active agent is doxorubicin.

29. The method of claim 7, wherein the active agent is selected from the group consisting of anesthetics, antihistamines, antineoplastics, antiulcers, antiseizures, muscle relaxants, immunosuppressants, anti-infectives, non-steroidal Body anti-inflammatory drugs, imaging agents, nutritional agents and mixtures thereof.

30. The method of claim 29, wherein said active agent is at least one antineoplastic drug.

31. The method of claim 30, wherein the active agent is doxorubicin.

32. The method of claim 9, wherein the active agent is selected from the group consisting of anesthetics, antihistamines, antineoplastics, antiulcers, antiseizures, muscle relaxants, immunosuppressants, anti-infectives, non-steroidal Body anti-inflammatory drugs, imaging agents, nutritional agents and mixtures thereof.

33. The method of claim 32, wherein said active agent is at least one antineoplastic drug.

34. The method of claim 33, wherein the active agent is doxorubicin.

35. The method of claim 10, wherein the active agent is selected from the group consisting of anesthetics, antihistamines, antineoplastics, antiulcers, antiseizures, muscle relaxants, immunosuppressants, antiinfectives, nonsteroidal Body anti-inflammatory drugs, imaging agents, nutritional agents and mixtures thereof.

36. The method of claim 35, wherein said active agent is at least one antineoplastic drug.

37. The method of claim 36, wherein the active agent is doxorubicin.

38. The method of claim 11, wherein the active agent is selected from the group consisting of anesthetics, antihistamines, antineoplastics, antiulcers, antiseizures, muscle relaxants, immunosuppressants, antiinfectives, nonsteroidal Body anti-inflammatory drugs, imaging agents, nutritional agents and mixtures thereof.

39. The method of claim 38, wherein said active agent is at least one antineoplastic drug.

40. The method of claim 39, wherein the active agent is doxorubicin.

41. The method of claim 12, wherein the active agent is selected from the group consisting of anesthetics, antihistamines, antineoplastics, antiulcers, antiseizures, muscle relaxants, immunosuppressants, antiinfectives, nonsteroidal Body anti-inflammatory drugs, imaging agents, nutritional agents and mixtures thereof.

42. The method of claim 41, wherein the active agent is at least one antineoplastic drug.

43. The method of claim 42, wherein the active agent is doxorubicin.

44. The method of claim 13, wherein the active agent is selected from the group consisting of anesthetics, antihistamines, antineoplastics, antiulcers, antiseizures, muscle relaxants, immunosuppressants, antiinfectives, nonsteroidal Body anti-inflammatory drugs, imaging agents, nutritional agents and mixtures thereof.

45. The method of claim 44, wherein the active agent is at least one antineoplastic drug.

46. The method of claim 45, wherein the active agent is doxorubicin.

47. The method of claim 3, wherein the hydrophilic polymer is bound to the phospholipid through a non-hydrolyzable bond.